This application relates to an automated sample handler for an analytical instrument in which racks holding capped or uncapped test tubes or other containers are input into and output from the instrument.
Many different types of sample handlers have been used in various analytical instruments to feed multiple test tubes into and out of the instrument. Several manufacturers have utilized a sample handler system whereby the sample handler comprises an input queue, an output queue and a cross-feed. The input queue consists of an area in which racks of test tubes are input into the instrument and are transported toward the cross-feed. The racks are then transferred to the cross-feed, where one or more racks may be at a given time. The racks are indexed at set positions along the cross-feed where operations are performed on the test tubes, such as aspirating samples from the test tubes, and the racks are then moved to the end of the cross-feed adjacent the output queue where they are output to the output queue. One such system is described in U.S. Pat. No. 5,207,986. Various methods are used to transport the racks within the input queue and output, queue. In some instruments, like the Chem I system sold by the Bayer Corporation, the input queue and output queue are indexed and walking beams are used to lift the base of the racks and translate them from one indexed position to an adjacent indexed position.
It is desirable to provide a sample handler that handles containers of various types, diameters and heights, whether capped or uncapped, and to permit a robotic arm to transport the containers to and from the sample handler for faster processing elsewhere without have to return the containers to a particular rack or position on the rack.
These prior art instruments do not provide this flexibility. First, they only handle a single type and style of test tube within a particular instrument. Second, these sample handlers are not designed to work in conjunction with a robot that removes containers, such as test tubes, individually from the racks for transport either within the instrument or between the instrument and a laboratory automation transport line. An entire rack would likely be lifted if a robot were to attempt to lift a test tube from a rack in the prior art instruments. Third, the input queue and output queue generally are not designed to handle uncapped test tubes because they do not stabilize the racks sufficiently and samples in open test tubes may spill. Fourth, the positions of the test tubes within a particular rack must be maintained or the instruments will be unable to track and perform the proper operations on the test tubes.
It is an object of this invention to provide an automated handler for feeding test tube racks, which may hold capped or uncapped test tubes, into an analytical instrument and output uncapped test tubes (also referred to as xe2x80x9copen test tubesxe2x80x9d) from the instrument after the contents of the test tubes have been sampled.
It is a further object of this invention to provide an automated handler from which individual test tubes and other containers can be retrieved from racks and returned to racks individually by a robotic arm.
It is a further object of this invention to provide an automated handler for an analytical instrument that is operable in either a freestanding mode, in which racks of test tubes are manually inserted into and removed from the handler, or as a subsystem in a laboratory automation system in which test tubes are retrieved from or returned to a transport line containing test tubes.
A first aspect of the present invention is directed to a sample handler for an analytical instrument having a feeder for handling a rack, which may hold containers. The feeder comprises left and right side walls of a substantially identical height, a walking beam mechanism, and a tray, having walls of a substantially identical height, that is moved by the walking beam mechanism. When the walking beam mechanism is activated, the tray lifts a rack, which has tabs on the left and right side of the rack at a substantially identical height, from the side walls of the feeder. The feeder may be an infeed or an outfeed of a sample handier. The tray in the feeder has asymmetric guide rails to prevent the rack from skewing in the tray.
Another aspect of the present invention is directed toward an analytical instrument having a sample handler that interacts with a robotic arm on the instrument. The sample handler has an infeed, cross-feed and outfeed. A rack is input to the instrument in the infeed and is then transferred to a track on a cross-feed of the sample handler. Pusher fingers beneath the track push the rack from behind the infeed to another position, preferably behind the outfeed, where the robotic arm removes containers for transport elsewhere in the instrument. An ultrasonic range sensor detects whether a rack has been inserted into the infeed and whether the rack is skewed when it is placed on the cross-feed track behind the infeed. A reader of machine-readable code, such as a bar code reader, and an ultrasonic liquid level sensor are positioned adjacent the track to identify the container and profile the containers before the robotic arm removes the containers from the rack.
Another aspect of the present invention is directed to a sample handler having an outfeed with a walking beam mechanism to move the racks with a movable tray. A rear area of the tray has side walls that have a plurality of detents separated by ridges to capture a rack within the detents and hold the rack in a fixed position for the return of containers to the racks.
Another aspect of the present invention is directed toward a sample handler having an infeed, cross-feed, outfeed, and stat shuttle. The stat shuttle provides for the inputting of containers on a priority basis, including containers that may otherwise be input on a rack placed in the infeed. The stat shuttle also permits the inputting and outputting of a variety of containers. Like the cross-feed, the stat shuttle has a bar code reader and ultrasonic liquid level sensor to identify and profile containers in the stat shuttle. Thus, containers that are unidentified or not properly profiled in the cross-feed may be transferred to the stat shuttle for another attempt at identification and profiling.